1487-49-6Relevant articles and documents
Nitrogen-doped cobalt nanocatalysts for carbonylation of propylene oxide
Chen, Lin,He, Lin,Xia, Chungu,Yang, Bingxiao,Zeng, Bo,Zhu, Gangli
, (2020)
Nitrogen-doped cobalt nanoparticles loaded on porous supports were developed for ring-opening carbonylation of propylene oxide. The catalysts were prepared by simply pyrolysis of Co(OAc)2/phenanthroline and supports. As proved by XPS combined with XRD and TEM characterizations, a higher amount of available Co-N sites were responsible for promoting the carbonylative activity. The selectivity of carbonylated products reached 93 percent, which is comparable to previously reported cobalt carbonyl catalysts. The novel type of carbonylative catalyst also could be reused and revealed fine stability due to the continuous generation of active [Co(CO)4]? species during reaction.
Novel pyridinium based cobalt carbonyl ionic liquids: Synthesis, full characterization, crystal structure and application in catalysis
Deng, Fan-Guo,Hu, Bin,Sun, Wei,Chen, Jing,Xia, Chun-Gu
, p. 4262 - 4267 (2007)
Through an optimized synthetic strategy, a series of novel alkylpyridinium cobalt tetracarbonyl salts, [C1Py][Co(CO)4] (2a), [C 4Py][Co(CO)4] (2b) and [C16Py][Co(CO) 4] (2c) (CnPy = N-CnH2n+1- pyridinium), were successfully prepared in good yields, using a water-organic biphasic system. All the three compounds melt well below 100 °C and could be classified as ionic liquids. The compounds were fully characterized using IR, UV-Vis, 1H NMR, 13C NMR, ESI-MS and elemental analysis, and 2c was structurally characterized by X-ray single crystal analysis. Compound 2b has been found to be an efficient and reusable catalyst for the alkoxycarbonylation of propylene oxide without the aid of a base additive. The Royal Society of Chemistry.
Baeyer-Villiger oxidation of an optically active 1,4-polyketone
Kosaka, Naoyuki,Hiyama, Tamejiro,Nozaki, Kyoko
, p. 4484 - 4487 (2004)
Baeyer-Villiger oxidation of poly[(S)-2-methyl-1-oxopropane-1,3-diyl] (1) with m-chloroperbenzoic acid provided poly(ketone/ester) (2) in a ratio of ketone/ester = 82/18 in 73% isolated yield. Methanolysis of 2 (Mn = 8600) gave only a trace amount of methyl 3-hydroxybutyrate (5) which resulted from neighboring two ester units, -[OCH(CH3)CH2C(=O)] 2-. The major product was oligoketone CMn = 650). A low yield of 5 indicates that an ester unit likely exists to distribute randomly in 2 rather than to form a block copolymer of a polyketone and a polyester.
Kinetics of the ring-opening carbonylation of ethyloxirane with hydrido tetracarbonyl cobalt
Kreisz, Jozsef,Ungvary, Ferenc,Sisak, Attila,Marko, Laszlo
, p. 89 - 97 (1991)
The rate of CO uptake in the reaction of HCo(CO)4 with ethyloxirane, which gives (3-hydroxypentanoyl)cobalt tetracarbonyl as the major product in an n-octane/methyl isobutyl ketone solvent mixture at 15 deg C, is first order with respect to HCo(CO)4 and e
Role of catalyst activation in the enantioselective hydrogenation of methyl acetoacetate over silica-supported nickel catalysts
Keane
, p. 372 - 381 (1994)
A range of Ni-SiO2 catalysts have been prepared by homogeneous precipitation-deposition and impregnation techniques and modified with aqueous solutions of R-(+)-tartaric acid (TA) to induce enantioselectivity in the asymmetric hydrogenation of a prochiral β-ketoester (methyl acetoacetate) to a β-hydroxyester ((R)-(-)-methyl 3-hydroxybutyrate). The effects of catalyst precursor preparation, nickel loading, and precalcination on the reduction of the precursor were examined and the nature of the resultant nickel particle size distribution is described. The influence of metal-support interactions on the uptake of TA was investigated and data on the corrosive metal leaching and the consequent changes in metal dispersion are presented. Modification of the catalysts with TA not only induced enantioselectivity, but also increased the turnover frequency by up to 15 times that observed for the unmodified surface. The amount of TA adsorbed and the fractional surface coverage by TA is related to the degree of enantiodifferentation. The effects of variations in supported nickel metal particle sizes (in the overall range of 1.4-13.6 nm) on the reaction rate and enantioselectivity were examined; while the selectivity was independent of metal particle size, the rate of hydrogenation was found to be structure sensitive and a correlation between reaction rate sensitivity and particle size is presented.
Process intensification for substrate-coupled whole cell ketone reduction by in situ acetone removal
Schroer, Kirsten,Tacha, Eva,Luetz, Stephan
, p. 836 - 841 (2007)
Three different reactor configurations for in situ acetone removal in whole cell biotransformation processes with substrate-coupled cofactor regeneration were applied. The reduction of 2,5-hexanedione to the corresponding (2R,5R)-hexanediol was catalyzed by recombinant Escherichia coli cells expressing an alcohol dehydrogenase from Lactobacillus brevis. The reaction was carried out in a substrate-coupled cofactor regeneration approach using 2-propanol as redox equivalent for intracellular cofactor regeneration. In contrast to a process without acetone removal, where 54% yield could be reached, the yield was increased to >90% when a pervaporation system was applied or when acetone was removed by sparging air through the reaction mixture. In a third system, conversion was driven using a biphasic system to extract acetone continuously from the biocatalyst containing aqueous phase and to allow high concentrations of the hydrophobic substrate 1-phenyl-2-propanone. When methyl tert-butyl ether was applied as the non-aqueous phase, only 24% yield was achieved. When the ionic liquid 1-butyl-3-methylimidazolium bis((trifluoromethyl)sulfonyl)amide was applied as the non-aqueous phase, >95% yield was reached as a result of the preferential partitioning behaviour of acetone over 2-propanol into the ionic liquid.
HYDROGEN PRESSURE DEPENDENCE OF THE ASYMMETRIC HYDROGENATION OF METHYL ACETOACETATE WITH MODIFIED NICKEL/SiO2 CATALYST
Nitta, Yuriko,Sekine, Fumimaro,Sasaki, Jun,Imanaka, Toshinobu,Teranishi, Shiichiro
, p. 541 - 542 (1981)
The optical yield of methyl 3-hydroxybutyrate in the asymmetric hydrogenation of methyl acetoacetate with tartaric acid-modified Ni/SiO2 catalyst decreased linearly with an increase in the hydrogen pressure up to 10 kg/cm2 in contraast to the data under higher hydrogen pressures.
Novel solid state reduction of organic functional groups on solid support (Merrifield's resin)
Chandrasekhar,Raza, Abbas,Padmaja
, p. 1061 - 1062 (1999)
Reduction of organic functional groups viz. aldehydes, ketones, esters and epoxides is achieved on solid support in solid state for the first time using NaBH4 and LiAlH4 under solvent free conditions.
Thermal decomposition of methyl β-hydroxyesters in m-xylene solution
Zapata, Edilma,Gaviria, Jair,Quijano, Jairo
, p. 92 - 96 (2007)
The products and kinetics of the thermal decomposition of several methyl-β-hydroxyesters in m-xylene solution have been studied. It has been shown that all β-hydroxyesters studied pyrolyze to form a mixture of methyl acetate and the corresponding aldehyde or ketone and that the decomposition follows first-order kinetics and appears to be homogeneous and unimolecular. The rate pyrolysis of methyl-3-hydroxypropanoate, methyl-3-hydroxybutanoate, and methyl-3-hydroxy-3-methylbutanoate has been measured between 250 and 320°C. The relative rates of primary, secondary, and tertiary alcohols at 553 K are 1.0. 8.5 and 54.1. respectively. The absence of large substituent effects indicates that little charge separation occurs during the breaking of carbon-carbon single bond. The activation entropy is compatible with a semipolar six-membered cyclic transition state postulated for other β-hydroxy compounds.
The Enantioface-differentiating (Asymmetric) Hydrogenation of the C=O Double Bond with Modified Raney Nickel. XXXIV. The Adsorption Mode of 2-Hydroxy Acid on Raney Nickel
Harada, Tadao
, p. 1019 - 1022 (1980)
The adsorbed species of the modyfying reagent and the surface states of the catalyst caused by the modification of a Raney nickel with 2-hydroxy acid at various pH regions were investigated.The adsorption mode of 2-hydroxy acid was proposed in each modifying-pH region; that is, (1) in a pH region intrinsic to the solution of the free 2-hydroxy acid, nickel salt of 2-hydroxy acid was adsorbed on the catalyst surface corroded by the acid; (2) under weakly acidic conditions, nickel salt and sodium salt of 2-hydroxy acid were adsorbed on the catalyst surface partially corroded by the acid; (3) under neutral conditions, the sodium salt was adsorbed on the surface of the fresh Raney nickel, and (4) under strongly basic conditions, the sodium salt and NaOH were adsorbed on the surface of the fresh Raney nickel.
